A short-range communication module that performs communication using a magnetic field formed in a frequency band of several to several tens of MHz is used in a radio frequency identification (hereinafter, referred to as RFID) module, a near field communication (hereinafter, referred to as NFC) module, and the like. In particular, various applications using an NFC method are used in portable terminals, such as mobile phones, and are gaining popularity as auxiliary payment devices.
As inductive wireless charging method, a Qi method of Wireless Power Consortium (WPC) and a Power Matters Alliance (PMA) method perform wireless charging using a low-frequency band in a range of 100 kHz. Meanwhile, NFC performs communication using a 13.56 MHz band, that is, industrial-scientific-medical frequency band (hereinafter, referred to as an ISM band), which is very different from the frequency band for the wireless charging method, and thus there is no problem due to little interference between the inductive wireless charging method and NFC.
In contrast, Alliance for Wireless Power (hereinafter, referred to as A4WP) using magnetic resonance uses a 6.78 MHz ISM band, which is very close to the 13.56 MHz ISM band of NFC, and thus power supplied from an A4WP power transmitting unit (hereinafter, referred to as a PTU) may be unintentionally supplied to an NFC module through an NFC antenna. Generally, an NFC module transmits and receives low power, and when a great amount of power is supplied thereto from the A4WP PTU, the NFC module may receive excessive power, and thus the NFC module may be broken.